Rotary regenerator



. 9,1969 J. w. BRACKEN, JR, ET AL 3,482,622

ROTARY REGENERATOR Filed Sept. 28, 1967 Jf Y m mfif mk N w m m n N United States Patent 3,482,622 ROTARY REGENERATOR Joseph W. Bracken, Jr., Redford, Township, and William S. Hubble, Livonia, Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Sept. 28, 1967, Ser. No. 671,267 Int. Cl. F28d 19/00, 17/00; F23c 15/02 U.S. Cl. 165-9 6 Claims ABSTRACT OF THE DISCLOSURE An annular matrix in an axial-flow regenerator which cooperates with circumferential seals bearing against the faces of the matrix at the outer rim has an impervious ring in the matrix structure blocking communication of pressure from one face of the matrix to the matrix-engaging face of the seal at the other face.

Our invention relates to rotary regenerators, particularly those of the axial-flow type. Such regenerators include a matrix which is a disk or drum of material pervious to flow through it in an axial direction, the matrix being rotated about its axis so as to cause each element of the matrix to pass alternatively through passages conveying fluids at different temperatures. Heat is stored in the matrix while exposed to one fluid and is delivered to the other fluid when it passes through it. It is customary to provide seals at the rims of the matrix to prevent flow around the matrix rather than through it. Such seals may extend entirely around the matrix on each side or may extend only part way around the matrix on One of the two sides. It is important that these seals bear lightly against the matrix to minimize friction and wear but that they be in contact to minimize leakage.

We have found that communication of pressure between the two faces of the matrix upsets the action of the seals. If the pressures can be communicated from face to face through the matrix to the seals, the effect is to provide communication through a connecting passage such that the pressure distribution exerted on the matrixengaging face of the inner seal is no longer independent of the pressure distribution exerted against the matrixengaging face of the outer seal.

. According to our invention, this difficulty is cured by providing some structure in the matrix which renders those portions of the matrix which contact the by-pass seal at the outer margin of the matrix impervious to fluid flow or transmission of pressure from one face to the other. In a preferred embodiment of the invention in which the matrix is of a ceramic type, the blockage is effected by cutting a channel into the outer circumferential portion of the matrix between the faces, which channel is filled with a ceramic material which is fired and hardened to form a barrier impenetrable to fluid between the faces of the matrix. Other means of providing such a barrier could be adopted, depending upon the structure of the matrix. The principle of the invention is applicable also to matrices of sheet metal structure.

The invention is illustrated here as embodied in a rotary regenerator of the type to which prior US. patent applications, of common ownership with this application, Ser. No. 655,174, filed July 21, 1967, of Bracken and Zeek for Regenerator Seals and our Ser. No. 661,075 filed Aug. 16, 1967, for Rotary Regenerator Matrix Mount and Drive, are directed. The specific structure illustrated is also illustrated in our prior application, except for the barrier means in the matrix which is the subject of this invention.

The principal objects of our invention are to improve the performance of rotary regenerators, to provide more ice precise and effective control over the contact forces of seals for such regenerators, to improve durabillty and minimize leakage in regenerators, and to provide a simple and effective means for eliminating imposition of static pressure from one face of a matrix on a seal WhlCh bears against the opposite face. While the principles of the invention may be applied to radial-flow regenerators, it is more readily applied to and more likely to find useful application in axial-flow regenerators, and is so shown.

The nature of our invention and its advantages will be clear to those skilled in the art from the succeeding detailed description of the preferred embodiment of the invention and the accompanying drawings thereof.

FIGURE 1 is a sectional view of a rotary regenerator taken in a plane containing the axis of rotation thereof.

FIGURE 2 is a fragmentary elevation view of one face of a matrix, with parts cut away.

FIGURE 3 is a fragmentary sectional view taken on the plane indicated 'by the line 33 in FIGURE 2.

FIGURE 4 is a greatly enlarged view of a portion of FIGURE 2, illustrating the general nature of the porous ceramic.

Referring first to FIGURE 1, a gas turbine engine may include an engine block or housing 9 which supports the rotating parts and combustion chamber of the engine (not illustrated) and which also supports a rotary regenerator R including an axial-flow matrix 10. The matrix is mounted for rotation about a horizontal axis, as illustrated, at a side face of the block 9. The matrix is enclosed by the block 9 and a regenerator cover 11 fixed to the block, these two constituting a housing for the matrix. The regenerator cover defines a cool air inlet 13 and an exhaust outlet 14. The block 9 defines a hot air outlet 15 opposite to the inlet 13 and a hot gas inlet 17 opposite to the exhaust outlet 14.

The ceramic matrix 10 is of known type embodying a hub or inner ring 18 by which it is driven, an annulus 19 of heat exchange material defining passages extending generally parallel to the axis from face to face of the matrix, and an outer ring or outer rim 20. The heat exchange material 19 is fixed to the hub 18 by a layer of vitreous cement 21. Seals cooperating with the matrix include an outer side rim seal 23 engaging the matrix adjacent the rim, an outer side hub seal 24 engaging the hub, an inner side rim seal 25 opposite to seal 23, and an inner side hub seal 26 opposite to seal 24. The sealing structure also includes radial 'crossarm seals extending from the hub to the outer margin of the matrix (not illustrated) to block flow from one fluid passage to the other across the face of the matrix. These seals may be as described in application Ser. No. 655,174.

The means for driving and supporting the matrix illustrated is the same as one form shown in our prior application referred to above. It includes a shaft 30 rotatably mounted in the housing driven by a sprocket 31. An inner coupling member 34 fixed on the shaft is coupled by a flexible ring to an outer coupling member 35 which connects the shaft to the hub 18 of the matrix.

We are not concerned with the details of structure or technology of the previously known matrix structure, such matrices being available commercially from the Coming Glass Works, Corning, NY. Techniques of preparing such cellular ceramic structures are the subject of US. patents. It may be noted, however, that the matrix is of such a nature as to provide numerous small passages or pores 37 extending parallel to the axis of the matrix. Generally speaking, this structure is made by laying up alternate spirals 39 of flat material and 40 of corrugated material. When the structure is completed it is fired.

The matrix embodying our invention includes one addition to the previously known structure. This is a barrier 42 extending inwardly from the rim 20 of the matrix, preferably near the median plane of the matrix. The barrier is impervious to fluid flow or pressure and extends radially inward from the rim a distance sufiicient to block off flow to the marginal portion of the matrix which makes contact with the circumferential seals 23 and 25. The barrier may be provided by sawing or otherwise forming a circumferential groove in the rim of the matrix and filling it with a ceramic material which hardens and bonds to the porous structure 19. Other means of providing the barrier in the matrix may, of course, be employed.

Precise control of the action of the seal and accurate response of the seal engaging force to the varying pressures which may exist in different conditions of regenerator operation are thus assured by presence of the barrier.

It would, of course, be possible to put a flow barrier on the face of the matrix engaging the seal. This is less feasible structurally than the internal barrier. Also, and more important, with our preferred structure the circumferential rim portion and the radial crossarm portion of the seal bear against the same cellular or honeycomb matrix structure, and thus operate more consistently and controllably.

The detailed description of the preferred embodiment of our invention for the purpose of explaining the principles thereof is not to be considered as limiting or restricting the invention, since many modification may be made by the exercise of skill in the art without departing from the scope of the invention.

What is claimed is:

1. A rotary regenerator comprising, in combination,

a housing,

an axial-flow matrix having radial faces and an outer circumferential surface, the matrix including heat exchange material defining multifarious distinct generally parallel passages from face to face of the matrix,

4 means mounting the matrix rotatably in the housing,

and

seal means mounted on the housing engaging at least one face of the matrix adjacent the outer surface of the matrix;

the matrix including barrier means within the matrix spaced from the seal means blocking the passages located adjacent the outer surface which communicate with the said seal means, so as to isolate the matrix-engaging surface of the seal means from expo-sure to pressure communicated through the matrix from the remote face of the matrix.

2. A regenerator as recited in claim 1 in which the said seal means engages only one face of the matrix throughout part of the circumference of the matrix;

3. A regenerator as recited in claim 1 in which the seal means extends around the circumference of both faces of the matrix.

4. A regenerator as recited in claim 1 in Which the matrix is composed of ceramic material.

5. A regenerator as recited in claim 4 in which the barrier means is a ring of impervious ceramic material extending radially inwardly from the outer surface of the matrix.

6. A regenerator as recited in claim 1 in which the barrier means is a ring of material impervious to flow extending radially inwardly from the outer surface of the matrix.

References Cited UNITED STATES PATENTS 3,392,776 7/1968 Topouzian -10 X ROBERT A. OLEARY, Primary Examiner ALBERT W. DAVIS, Assistant Examiner US. Cl. X.R. 165-10 

